Clipping mechanism piston actuator

ABSTRACT

A clip applying machine for tubular casings often comprises opposing clip jaw members that pivot toward each other to gather the casing and position a die member on one side of the casing. A punch member is advanced from the other side of the casing to feed a clip around the casing and against the die member. The jaw members are pivoted by a piston/cylinder mechanism which is pivotally connected to the jaw members and the punch is advanced by another piston. A knife is advanced to sever the casing in the area of the clip. In such a machine, an improved piston cylinder arrangement includes the piston having a central bore, with an inner rod in the cylinder passing into the piston. The inner rod and piston together form a closed fluid passage into the piston such that pressurized fluid in the passage tends to put and keep the piston in a retracted position. The piston cylinder combinations are also “cascaded” such that on advancement of a first piston, the fluid driving the first piston ports to drive a second piston, and thereon, causing the piston cylinder combinations to act in series.

BACKGROUND OF THE INVENTION

[0001] This invention relates in part to packaging machinery, and more particularly to packaging machines for food processing, such as stuffing machines of the type that make sausage chubs and similar stuffed meat and stuffed food products. Most particularly, this invention relates to an improved clipping mechanism in and for a chub forming machine.

[0002] Sausage making and the making of similar stuffed meat and food products has become highly automated. As a result of significant, valuable research in the United States, a variety of machines have been successfully developed for the automated and semiautomated production of chubs from processed meats and casing. One such machine is disclosed in U.S. Pat. No. 4,766,713, issued on Aug. 30, 1988 to Alfred J. Evans, for a Packaging Device Including Dual Clip Attachment Apparatus, incorporated by reference. In a machine such as that disclosed in the identified patent, sausage material is pumped from a vat to a stuffing horn assembly. Shirred casing is applied over the end of a stuffing horn. The casing and material pumped to the horn leave the horn simultaneously, through a casing brake. The stuffing material fills the casing and the casing maintains the material under slight pressure. The casing brake permits the casing to exit under uniform tension. Adjacent the casing brake, dual product clippers intermittently acts to void sections of the casing which have passed, the brake, into voided “rope” sections. The clippers clip each rope section to define the end of an exiting chub and the beginning of the next chub.

[0003] Other notable machines are disclosed in U.S. Pat. No. 4,675,945 issued on Jun. 30, 1987 to Alfred Evans et al., U.S. Pat. No. 4,847,953, U.S. Pat. No. 5,077,955, U.S. Pat. No. 5,644,896 to Evans et al., U.S. Pat. No. 5,755,022 to Whittlesey, and U.S. Pat. No. 5,916,019 to Whittlesey, all incorporated by reference. In the machines of the identified patents, clipping mechanisms are provided for supplying and deforming metal clips about the voided casing. The clipping mechanicms, i.e., clippers, are generally of two types: throat type and gate type.

[0004] While the machines of U.S. Pat. No. 4,766,713 and the other identified patents have proven highly desirable, continued advances have been desired in clipping mechanisms, knife mechanisms, and associated mechanisms, to decrease the size of the mechanisms, reduce the number of parts of the mechanisms, simplify adjustments, repairs and replacements of the mechanisms, dramatically reduce the air volume and pressure requirements of the mechanisms, extend the life of the mechanisms, and package the mechanisms into self-contained units.

[0005] As a result of recent advances in the identified machines, the machines have found applications outside the food industry. This inventions relates, therefore, to all industries where the identified machines have found application.

SUMMARY OF THE INVENTION

[0006] In and for a chub packaging machine, the invention is directed, in a principal aspect, to an improved piston cylinder arrangement that includes the piston having a central bore, with an inner rod in the cylinder passing into the piston. The inner rod and piston together form a closed fluid passage into the piston such that pressurized fluid in the passage tends to put and keep the piston in a retracted position. The packaging machine of the invention is for applying clips to rope sections of filled tubular casing to form chubs, the machine having at least one clipping mechanism including at least one tool. The piston is movable in the cylinder, and is affixed to the punch for driving the tool. The improved piston cylinder arrangement may be the main piston cylinder, for driving the punches of the machine, or may be for driving a knife of the machine, or any other driven tools.

[0007] The cylinder may further include a head block. The inner rod may be affixed to the head block. The piston may be slidable relative to the inner rod. The inner rod may form an inner rod internal bore, the piston may form a piston internal bore, and the inner rod further may form an opening from the inner rod internal bore to the piston internal bore. Thus, the closed fluid passage may include the inner rod internal bore, the opening, and the piston internal bore, and the head block and inner rod may continue the fluid passage into the head block. The piston cylinder arrangement may be pneumatic, with the pressurized fluid being a gas, and the closed fluid passage being a closed pneumatic passage. The piston will have a drive surface, and the cylinder and piston will form a chamber therebetween for introducing a drive fluid between the cylinder and piston to drive the piston in the cylinder against the tendency of the pressurized fluid, to advanced positions of the piston and tool. The drive fluid will be cycled to reciprocate the piston in the cylinder between the advanced position and the retracted position.

[0008] Further, the clipping mechanism may include a second tool, with the first tool being, for example, a punch and the second tool being, for example, a knife. In that case, the piston and cylinder arrangement may further comprise a second cylinder and a second piston movable in the second cylinder. The second piston will be affixed to the knife for driving the knife, and the first cylinder will be ported to port the drive fluid to the second cylinder on advancement of the first piston to the advanced position of the punch, the second cylinder and second piston forming a second chamber therebetween for introducing the drive fluid ported from the first cylinder between the second cylinder and second piston to drive the second piston in the second cylinder to an advanced position of the knife, after the punch has reached its advanced position. In this way, the piston cylinder combinations will be “cascaded” such that on advancement of a first piston, the fluid driving the first piston ports to drive a second piston, and thereon, causing the piston cylinder combinations to act in series.

[0009] Filled tubular casing moves through the chub packaging machine. The path of movement of the filled tubular casing defines a longitudinal axis. This axis is a significant physical direction for understanding orientation of the structure of the machine. The support structure of the invention defines a jaw cylinder, and the jaw cylinder extends in a direction which is transverse, relative to the longitudinal axis. Within the jaw cylinder, a piston member moves transversely under force of pressure. The clip jaw members are pivotally mounted to the support structure for pivoting relative to the support structure toward each other, to and from a closed position. A die member for clip deformation is located on one of the clip jaw members. The mechanical link members are pivotally mounted to the jaw piston member, for movement with the jaw piston member, and pivotally attached to the clip jaw members, for driving the pivoting of the clip jaw members relative to the support structure. Thus, transverse movement of the jaw piston under force of pressure pivots the clip jaw members closed.

[0010] A punch is affixed to a piston member as described above, for transverse movement with this punch piston member, into and out of cooperative interaction with the die member while the clip jaw members are in the closed position. The knife will be similarly positioned and driven.

[0011] A pressurizing means pressurizes piston cylinders in coordination, as necessary, to move the pistons in coordination, to advance the clip jaw members to the closed position, thereafter drive the punch into cooperative interaction with the die, and drive the knife. Clips fed successively to the clipping mechanism are driven under action of the punch around successive rope sections of the filled tubular casing and deformed to clip the rope sections. The clip jaw members, punch and knife are intermittently actuated and retracted during passage of filled tubular casing along the path of movement, to provide for movement, clipping and severing of the filled tubular casing.

[0012] This principal aspect and other principal aspects of the invention are more full appreciated by a reading of the detailed description of the preferred embodiment of the invention, which follows.

BRIEF DESCRIPTION OF THE DRAWING

[0013] The accompanying drawing illustrates the specific preferred embodiment of the piston cylinder arrangement of the invention. Familiarity with the machines of the patents incorporated by reference is assumed. The structure of the drawing is not the only form which the invention as claimed may take. The drawing and the following detailed description of the preferred embodiment are intended to limit the claims only as consistent with the law of claim interpretation, whereby claims are interpreted in light of the specification and drawing.

[0014] The description which follows may refer to the componentry of the machine in such spatial terms as “front,” “rear,” “upper,” “lower,” “left,” “right,” etc. Terms such as these, which depend on the specific spatial orientation of the components, are intended for the aid of the reader, and except as incorporated into the claims, not as a limitation on the possible orientation of components in any possible alternate, but covered, embodiment of the invention. Except as consistent with the law of claim interpretation, the drawing and following description are only illustrative of the invention.

[0015] For orientation of the reader to the drawing, and for ease of beginning of reading of the following detailed description, a brief description of the drawing is as follows:

[0016]FIG. 1 is an external, side view of the cylinder of the preferred embodiment of the invention;

[0017]FIG. 2 is an external, end view of the cylinder of FIG. 1; and

[0018]FIG. 3 is a internal, cross-section view of the preferred piston cylinder arrangement of the invention, taken along the longitudinal centerline of the cylinder and splitting it in half, front to rear, to lay open internal detail. More specifically, the arrangement is split open along line A-A in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] The preferred form of the invention is embodied in a preferred form of packaging machine having a clipping mechanism positioned along the path of movement of filled tubular casing. The path of the casing defines a longitudinal axis, and extends through a throat area of the mechanism. The path of the casing is typically horizontal, and the mechanism as preferred extends generally above the path. A voiding mechanism, not a part of the invention, accompanies the clipping mechanism and extends below the path. A clip feed mechanism and a loop feed mechanism, also not part of the invention, also accompany the clipping mechanism.

[0020] The clipping mechanism includes a main assembly within a main housing. A foot plate provides for mounting of the clipping mechanism where desired. Rising over the foot plate, a voider portion of the housing contains the voiding mechanism. Continuing upward, a longitudinally narrowed and transversely widened portion of the housing contains pivotal clip jaws.

[0021] An upper cylinder housing contains an upper cylinder assembly. The upper cylinder housing is fastened atop the main housing assembly. Clip reels and clip rails of the clip feed mechanism are mounted to the sides of the upper cylinder housing. A loop reel of the loop feed mechanism is also mounted to the cylinder housing. Clips are fed from the reels onto the clip rails and by the rails to a clip window in a portion of the main housing.

[0022] Internally, the upper cylinder housing opens into the main housing, through the central portion of a mounting lug.

[0023] Briefly, a pair of pneumatically driven pistons in the upper cylinder assembly drive pivotal clip jaws in the main assembly and punches which move through the housings. The pistons drive the jaws and punches in a coordinated motion, into and out of the throat area, transversely to the path of the casing. With each movement into the throat area, the jaws close and the punches advance, driving clips against dies on the jaws, and deforming the clips around rope sections of the filled tubular casing. The pistons are advanced and retracted between retracted, or “stand-by,” positions and advanced, or “clipping,” positions. Advancement of the pistons occurs under action of pneumatic pressure from a pneumatic manifold. Air transfer ports open from the manifold into the cylinders. Pressurized air through these ports drives the pistons.

[0024] In the past, return of the pistons to the retracted positions occurred under action of helical springs, on venting of the ports. The springs were compressed during advancement of the pistons, and recoiled to return the pistons.

[0025] The clip jaws meet in the advanced position to define punch channels for guidance of the punches. One of the clip jaws defines die pockets with dies therein. The dies crimp clips driven into the dies by the punches. The clip jaws are linked by links each comprised of telescoping link members to the jaw piston.

[0026] The machine also includes a pneumatically driven cut-off knife, driven in a slot by a knife piston and rod. Action of the knife is coordinated to result in a sequence of operation of clip jaw advance, punch full advance, knife advance, knife retraction, partial punch retraction and full punch and clip jaw retraction.

[0027] In this preferred machine, the preferred embodiment of the invention includes improved piston and cylinder arrangements for driving the tools of the machine, including the jaws, the punches and the knife. The improved piston and cylinder arrangements are located and positioned on their machine where appropriate and necessary to properly drive their associated tools.

[0028] Referring to FIG. 1 of the drawing, the piston cylinder arrangement as most preferred is incorporated in a cylinder body 1. A cap top 2 and a valve cover 22 are attached. Referring to FIG. 2, the cap 2 is held to the cylinder body 1 by fasteners 21, and is removable for repair, to permit replacement of parts including the associated punch. A quick connect fitting 25 leads to a valve 29, thereby to a nipple 24 and into the cylinder body 1, as will be described. A muffler fitting 28 leads to a muffler 27. The valve cover 22 is held to the body 1 by fasteners 23.

[0029] Referring to FIG. 3, important internal details of the piston cylinder arrangement are revealed. The piston cylinder arrangement being described is specifically adapted to drive a punch. According, a punch main piston 5 is in the piston cylinder body 1. The piston 5 is externally cylindrical, and slidable along the internal cylindrical walls of the body 1, which are closely dimensioned relative to the external wall of the piston. A U-cup seals any gap between the piston wall and the body walls. The piston moves in the directions defined by the centerline of the body 1, from left to right and right to left in FIG. 3, and generally transversely to the path of casing.

[0030] At the right end, the body 1 is completed and closed by a head block 30 formed by the cap top 2. The cap top is fastened to the body 1 through the fasteners 21, as at the bottom right corner of FIG. 3. An O-ring 20 encircles a groove of the head block and abuts that groove and the inner wall of the body 1, sealing the head block 30 and body 1 together. An O-ring 19 also seals the valve cover 22 to the cap top 2. At the left end, the body 1 is open.

[0031] An inner rod assembly including an inner rod 3 extends from the head block 30 along the centerline of the body 1. The rod 3 and body 1 are concentric with each other, i.e., centered on each other's centerlines. An O-ring 4 encircles a groove in a flanged bushing on the rod 3, sealing the rod 3 and head block 30. The piston rides the rod 3, as well as the cylinder body walls, along a piston extension that extends from the piston head. A fastener 11 holds a punch piston stop 7 to the rod 3, at its end distant from the head block 30. A U-cup 8 and a wear strip 9 encircle the outer perimeter of the stop 7. Interior to the piston head, a piston gland 12 fits in a recess in the piston head, and is held in place in the recess by a retaining ring 14. An O-ring seals the inner wall of the recess and the outer perimeter of the gland 12. An O-ring 16 seals the outer perimeter of the rod 3 and the inner perimeter of the gland 12. A bushing 17 also interposes the rod 3 and gland 12, and is held by a retaining ring 13.

[0032] Together, the stop 7 and the gland 12, and their associated wear strip, U-cup, O-ring and bushing, permit the piston extension and thereby the whole of the piston 5 to ride smoothly along the rod 3. The piston may travel between contact of an O-ring 18 in a recess in the face or drive surface of the piston head with the inner end wall of the head block 30 and contact of the backside of the piston head with the beginning of the left-end, reduced diameter wall of the cylinder body 1 which forms a stop for travel of the piston head.

[0033] As can be seen, the piston 5 and head block 30 form a chamber therebetween for introduction of a drive fluid between the piston face or drive surface and the inner end wall of the head block. The drive fluid is introducible through an opening into the chamber through the headblock, and control of the drive fluid is provided by valving including a cartridge valve 26. As may be anticipated, the piston 5 is intermittently driven to advance the punch attached to the piston (attachment not shown).

[0034] Also, inner rod 3 forms an inner rod internal bore 31, and the piston 5 forms a piston internal bore 32. The inner rod 3 also defines an opening 33 from the bore 31 to the bore 32. The piston internal bore extends between the right face of the stop 7 and the left face of gland 12. The inner rod internal bore extends from the right face of the fastener 11 into the head block 30, and into passageways through which constant pneumatic pressure is applied to the closed fluid passage formed in the inner rod 3 and piston 5.

[0035] With the piston, cylinder, inner rod, and defined chamber and closed fluid passage, the preferred piston cylinder arrangement is able to operate with the pneumatic pressure applied to the closed fluid passage tending to retract the piston against the head block whenever the pneumatic pressure is applied to the closed fluid passage. Against this tendency, drive fluid is applied to the piston drive surface between that surface and the head block in the form of intermittent pneumatic pressure preferably significantly greater than that applied to the closed fluid passage. This pressure increase works in combination with the significantly increased surface area of the drive surface relative to the surface on which the “retracting fluid pressure” is acting. The pressure increase and the surface area increase, or the surface area increase alone in a situation of not-increased pressure, overcomes the retracting fluid pressure, permitting the piston to be intermittently driven to an advanced position, thereby advancing the associated tool, in this case, in the form of the attached punch (not shown).

[0036] On venting of the drive pressure, as through the muffler, the piston retracts. No mechanical springs are needed, as they are for example in the structure of U.S. Pat. No. 5,077,955. Accordingly, the piston is intermittently drivable to advanced positions to advance its associated tool, and retractable for readiness of next drive strokes.

[0037] Also, when the retracting fluid pressure on the closed passage is removed, the piston is rendered immobile, without the residual pre-loading of a mechanical spring, and the piston cylinder assembly is rendered easy to disassemble.

[0038] Moreover, as most preferred, piston cylinder arrangements of the described type are “cascaded.” Referring again to FIG. 3, as most preferred, a port 34 is located in the sidewall of the cylinder body 1, at a location the piston 5 passes as it drives to its advanced position. The drive fluid in the chamber between the piston 5 and the headblock 30 is available through the port at the point in time when the piston 5 passes the port 34. As a result, the drive fluid in the illustrated drive cylinder arrangement may be utilized in another similar or even another dissimilar piston cylinder arrangement to drive another piston to the advanced position of another piston and another tool, and thereon. Multiple tools may be driven in sequence through the porting, with tools driven in series.

[0039] The preferred embodiment and the invention are now described in such full, clear, concise and exact terms as to enable a person of skill in the art to make and use the same. To particularly point out and distinctly claim the subject matter regarded as invention, the following claims conclude this specification. 

1. In a packaging machine for applying clips to rope sections of filled tubular casing to form chubs, said machine having at least one clipping mechanism including at least one tool, an improved piston and cylinder arrangement, comprising: a cylinder; a piston movable in the cylinder, the piston affixed to the punch for driving the tool, the piston having a central bore; and an inner rod in the cylinder passing into the piston, the inner rod and piston together forming a closed fluid passage into the piston such that pressurized fluid in the passage tends to put and keep the piston in a retracted position.
 2. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, in which the tool is a punch.
 3. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, in which the tool is a knife.
 4. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, the cylinder including a head block and the inner rod affixed to the head block.
 5. In the packaging machine of claim 4, an improved piston and cylinder arrangement as in claim 4, the head block and inner rod continuing the fluid passage into the head block.
 6. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, the inner rod forming an inner rod internal bore, the piston forming a piston internal bore, and the inner rod further forming an opening from the inner rod internal bore to the piston internal bore, the closed fluid passage including the inner rod internal bore, the opening, and the piston internal bore.
 7. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, the piston slidable relative to the inner rod.
 8. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, the cylinder including a head block, the inner rod affixed to the head block, and the piston slidable relative to the inner rod, the inner rod forming an inner rod internal bore, the piston forming a piston internal bore, and the inner rod further forming an opening from the inner rod internal bore to the piston internal bore, the closed fluid passage including the inner rod internal bore, the opening, and the piston internal bore, and the head block and inner rod continuing the fluid passage into the head block.
 9. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, the pressurized fluid being a gas, and the closed fluid passage being a closed gas passage.
 10. In the packaging machine of claim 1, an improved piston and cylinder arrangement as in claim 1, the piston having a drive surface, the cylinder and piston forming a chamber therebetween for introducing a drive fluid between the cylinder and piston to drive the piston in the cylinder against the tendency of the pressurized fluid, to advanced positions of the piston and tool.
 11. In the packaging machine of claim 10, an improved piston and cylinder arrangement as in claim 10, the pressurized fluid being fluid at a substantially constant pressure.
 12. In the packaging machine of claim 11, an improved piston and cylinder arrangement as in claim 11, the drive fluid and pressurized fluid both including air, the drive fluid being cycled to reciprocate the piston in the cylinder between the advanced position and the retracted position.
 13. In the packaging machine of claim 10, an improved piston and cylinder arrangement as in claim 10, the clipping mechanism including a second tool, the first tool being a punch and the second tool being a knife, the piston and cylinder arrangement further comprising: a second cylinder; a second piston movable in the second cylinder, the piston affixed to the knife for driving the knife; and the first cylinder being ported to port the drive fluid to the second cylinder on advancement of the first piston to the advanced position of the punch, the second cylinder and second piston forming a second chamber therebetween for introducing the drive fluid ported from the first cylinder between the second cylinder and second piston to drive the second piston in the second cylinder to an advanced position of the knife, after the punch has reached its advanced position.
 14. An improved piston and cylinder arrangement as in claim 13, the second piston having a second central bore; and a second inner rod in the second cylinder passing into the second piston, the second inner rod and second piston together forming a second closed fluid passage into the second piston such that pressurized fluid in the second passage tends to put and keep the second piston in a second retracted position. 